The present invention generally relates to portable electronic devices. In particular, the present invention relates to a system and method for power management in a portable electronic device.
Portable electronic devices (e.g, notebook computers, mobile data terminals, radio frequency portable communication devices, etc.) typically include a rechargeable or alkaline battery to supply power to the portable device. These devices also typically employ a secondary power source to ensure that data stored in a Random Access Memory (RAM) device is not lost in the event that the main battery becomes disconnected from the portable device. The main battery may become disconnected if the portable electronic device is dropped, or if the main battery is being swapped with a new main battery. The bridge battery is usually a smaller battery because during a battery swap, the portable device normally will enter a low current or suspend mode, so that most current drawn from the bridge battery is used to refresh the RAM device, until a new main battery is installed into the device.
Many portable devices employ complicated switching or logic circuitry when changing from the main battery power to the bridge battery power. The switching or logic circuitry takes up valuable space on a circuit board that could be utilized to perform the functions of the portable device. In some cases, additional circuit boards are necessary to house the switching or logic circuitry. Furthermore, some of these portable devices employ expensive power management and supervisory circuitry to cause the functional components in the portable device to enter different modes, depending on the type of unit powering the portable device or the current status of the unit powering the portable device. The additional power management and supervisory circuitry adds to the size, the cost and also to the complexity of the portable device.
Accordingly, there is a strong need in the art for a system and/or methods that can provide power distribution for a portable electronic device at low cost, while reducing space utilized in employing such a system.
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is intended to neither identify key or critical elements of the invention nor delineate the scope of the invention. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.
The present invention relates to a power management system for a portable electronic device. The power management system provides supplemental power to the portable electronic device in the event that the main battery becomes disconnected from the portable electronic device. Thus, in accordance with one aspect of the present invention, a power management system is provided for a portable electronic device that includes a battery and a super capacitor electrically connected to the battery. The super capacitor is employed to provide power to the portable electronic device power supply when the battery loses connection with battery contacts.
In accordance with another aspect of the present invention, a system is provided for compensating the internal impedance of a battery in a portable electronic device. When the internal impedance of a battery rises to a predetermined level, the low internal impedance of a super capacitor is employed to compensate for the battery""s high internal impedance, thus preventing a voltage drop in the system.
In accordance with another aspect of the present invention, a system is provided in which a battery and a super capacitor share a load. The battery and the super capacitor are connected electrically in parallel and are able to drive a common load while distributing the demand placed on the battery and super capacitor in accordance with their respective capacity and power capabilities.
In accordance with yet another aspect of the present invention a method is provided for supplementing a power source for a portable electronic device. The method includes: providing a battery to the device, the battery being employed to power the device as long as the battery remains connected to the device, and providing a super capacitor to the device. The super capacitor is employed in the event that the battery becomes disconnected from the device and/or the ability of the battery to provide a suitable level of power to the device is diminished.
In accordance with yet another aspect of the present invention, a method is provided for compensating the internal impedance of a battery in a portable electronic device. The method includes, providing a battery to the device as a main power supply and providing a super capacitor electrically connected to the battery, the super capacitor being operable to balance the internal impedance of the battery. As the internal impedance of the battery rises, the low level of the internal impedance in the super capacitor balances out the high internal impedance of the battery to prevent a voltage drop out in the system.
To the accomplishment of the foregoing and related ends, the invention then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative aspects of the invention. These aspects are indicative, however, of but a few of the various ways in which the principles of the invention may be employed and the present invention is intended to include all such aspects and their equivalents. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.